Conventionally, a video game device is known such a kind of image processing device. The video game device is connected to a monitor device such as a CRT or a liquid crystal display. An image of a foreground such as a character coming on a game is superimposed with an image of a background and is displayed on the monitor device. The game is played by changing the foreground image and the background image in response to a control signal input by the player.
The foreground contains an object (character) having motion, such as a human being or an animal. The motion of the character is represented by changing its position and shape on the display. For example, the motion of a player character, which is a character directly controlled by the player, is represented so that the position and shape of the player character is changed in accordance with the control signal given by the player.
Conventionally, in order to represent the motion of the character and the like by a change of its shape, still pictures having different shapes are produced beforehand and are stored in a non-volatile memory such as a ROM. A series of motion is represented by sequentially reading the still pictures from the memory. The still pictures may be artificially produced or pictures extracted from a natural picture taken by a video camera in a time-lapse way.
The technique of representing the motion of the character by means of the still pictures can reduce the capacity of the memory to be built in the video game device, while it provides an unnatural motion of the character and the player feels insufficient reality during play of the game.